For John Bozzelli, owner of Injection Molding Solutions, getting the basics right has always been fundamental to the injection molding process. He has long been a passionate advocate for competitiveness in North American plastics manufacturing. In addition, for the last 20-plus years, he has taught practical techniques for bringing science and technology into the molding process.
Bozzelli graduated from Marietta College, Marietta, Ohio, in 1968, with a bachelor's degree in chemistry. His studies were interrupted when he was drafted in 1969 for deployment in Vietnam with the U.S. Army. He served in a company that, by his description, was used as bait, walking up and down trails until the soldiers were ambushed. He lasted 65 days before being severely wounded by a B-40 rocket. Bozzelli describes that experience as the signature event that drives his life.
"I should never have survived," he said. After being discharged with a Purple Heart and Silver Star, Bozzelli earned a master's degree in chemistry from Ohio University, Athens, in 1972.
He recently spoke with Plastics Machinery Magazine senior correspondent John DeGaspari.
Tell us about your early years in the plastics industry.
Bozzelli: I went to work for Dow [Polymer Research] from 1972 to 1982. I had a nice job at Dow making new polymers. Dow had a very good work culture; I had excellent bosses. They also gave you $1,000 to buy what you needed for work without asking anybody. They encouraged skunk works [an experimental lab], where you can do what you wanted to do, as long as it did not hold up your main project.
In 1982, I [transferred] to Dow's Tech Service. I was introduced to an injection molding machine. I started on a reciprocating-screw Negri Bossi. Nobody could fully answer my questions about plastics processing. It is absolutely amazing that resin manufacturers do not know how to process and machine manufacturers do not know how to process. Resin manufacturers know how to make resin; they do not know how to process. Machine manufacturers know how to make machines, but they do not know processing.
How did you begin to gain an understanding of plastics processing?
Bozzelli: [Dow] had bought a brand-new Arburg; we tore it all apart and figured out how it worked. I went to every possible plastics processing course I could find … good seminars but they were not explaining the science behind processing. Glenn Beall [president of Glenn Beall Plastics Ltd.], John Klees [retired president of John Klees Enterprise Inc.] and Rod Groleau [former chairman of RJG Inc.] provided better insight, but still, pieces were missing.
I contracted [with Groleau] while at Dow. We researched processing. I was doing processing research while he was trying to develop his process monitoring equipment. Between those two things, bits and pieces came together. The machines had developed from plunger to reciprocating screws. The machines went from having only one stage — which is the way I started — with no way of switching from fill to pack and hold, to [having] two stages.
When was this?
Bozzelli: By the early 1980s, plungers were history and we had newer, but still all-mechanical, screw machines. Ten to 15 years later, machines evolved and we were into computer controllers. Then, we bought a machine that not only plotted pressure vs. time but also integrated the curve. This made us think about monitoring viscosity via the integral. Rod and I did the first on-machine viscosity curves, and plotted the data linearly rather than the traditional log-log method. The log-log method shows the dramatic viscosity change. That is, you can see viscosity of the polymer change by an order of magnitude by changing fill time. It is easier flowing at high shear rates and stiffer at low shear rates. Using this and other data, bit by bit we got pretty successful in building and troubleshooting plastics processes. This in turn helped me develop and service Dow's customers.
I worked for Dow from 1972 until 1992, and then I went to work for Rod at RJG for two years. Then I started my own company, Injection Molding Solutions.
What would you like to see from machinery manufacturers as far as understanding the process?
Bozzelli: One thing [molders] can do for their company is that whoever designs the part, that person has to stay with the project until it is in 24/7 production. He should be at all trials and in all meetings.
Processors in North America ought to unite and require all of the machine manufacturers to have five controller screens that are identical. For me, it would be the temperature screen, injection screen, charge/rotate screen, clamp and a screen to monitor important parameters while in production. The five screens [should be] identical so the processors can go from one machine to another under real-life, demanding conditions of production, and easily understand what the numbers mean as they program each different machine. There is also a timing issue, where actual pack and hold times differ among different presses [depending on whether they use series timing or parallel timing]. If you do not have the same [timing] process, you are not making the same part. Machine manufacturers need to explain these subtleties so processors know how their machines work.
What do you recommend to the molder for setup?
Bozzelli: Molders should have a [common] set-up sheet. Better yet, all should be using one set-up sheet per mold, not per machine. I call it a universal set-up sheet. You are going to use the same numbers on every machine for a given mold. You have one set-up sheet per mold. You make the machine give you the same values and the same results, like fill time. You duplicate what really is happening — not set points. There is a huge difference. First, you have to measure it; the machine has to tell you what the right fill time is. The timers, gauges, transducers have to provide accurate data. You have a list of parameters that document a process. This is how you build a process. If it is a new mold, you do not rush to make a good- looking part; you take the appropriate time to test the mold to find all of the problems with it before you go into production.
What advice do you offer to molders shopping for new injection presses? What should they be looking for?
Bozzelli: One of the things they need to do is make a list of what they need. Typically, they wait until a machine dies or they have a brand-new project that is just starting up and they need a machine next week. There is very little planning.
Also, know that machine requirements change for different parts. Spend a little bit more money to get extra options that are commonly used for other projects. One issue often ignored is how much pressure the machine can develop. They go for the biggest barrel, while the trend in the last 15 years is more cavities, longer flow paths, more complicated flow paths, more complex parts. All of these developments need more pressure to fill the parts. In my classes, I advise: Do not buy a machine that cannot reach 30,000 psi. Thin-wall molding? Look at 40,000 psi and above.
What common problems do you find when doing machine audits?
Bozzelli: As mentioned previously, many are pressure limited. Switchover from first stage to second stage is usually a problem. Most of the electrics can handle it a little bit better than the hydraulics, but there are still problems, especially with the pack velocity. Machine manufacturers handle this differently; few of them have a handle on it and there is little to no training for it.
Do you have a wish list of technology improvements?
Bozzelli: Yes, first would be the ability to measure temperature on the fly. Then there is using open loop for second stage. First stage [can be] closed loop, but use open loop on second stage. That would be much easier, take many of the programming hassles out of our hands and provide better response. The problem is the controlling aspects of it. When you have [closed-loop feedback in the second stage] there are problems for the initial second or two. It is wiser, cheaper, easier and performs better if they go open-loop.
How would you like to be remembered?
Bozzelli: That I brought a little bit of the science and technology to the forefront and tried to push science into our processing; that I took the processor's view in bringing in the science and technology; that I elevated the appreciation for those skilled tradesmen who run injection molding machines. Finally, I brought more respect for the importance of manufacturing within our society.
